As a memory card (or storage card) for storing data, such as a PCMCIA ATA Flash Card (PC card), a Compact Flash Card (CF card), a Smart Media Card (SM card), a Multi-Media Card (MMC card), a Memory Stick Card (MS card), a Secure Digital Card (SD card), a Micro Driver card, a chip card, and an XD, etc has the high-capacity, rewritable, vibration-resisting, light, thin, short and compact features, the memory card is thus used extensively for the data storage of computers and digital electronic devices such as a notebook computer, a personal digital assistant (PDA), a digital camera (DSC), and a MP3 players, etc, and these types of memory cards are accessed through a card reader. The card reader is generally comprised of a card adapter and a circuit board. At present, the card adapter is developed with a universal design for adapting various different memory cards. Please refer to FIG. 1 for a perspective view of a prior art.
In FIG. 1, a traditional memory card adapter comprises a base 1′ consisting of a plank base 11′, an upper panel 12′ and a lower panel 13′, and both upper and lower panels 12′, 13′ are installed on the plank base 11′ having a plurality of contact members 18′ electrically connected to a memory card of various different types, when such memory card is inserted.
One side of the plank base 11′ is an open insert end for receiving the insertion of a memory card, and the space inside the insert end is used for stacking the memory cards so as to reduce the space occupied by the slots and form a plurality of card slots 14′, 15′ 16′ for accommodating a plurality of memory cards of different models and sizes such as a SM card as shown in FIG. 1A, a MS card as shown in FIG. 1B and a SD card as shown in FIG. 1C respectively.
Please refer to FIG. 2 for a schematic side view of a prior art. In FIG. 2, a structure of an adapter 2″ is used for receiving and fixing several storage cards of different specifications which are not inserted at the same time. The structure has an upper casing 21′ and a first PCB 22′ disposed at a corresponding position, and the upper casing 21′ and the first PCB 22′ include a metal contact lead terminal 27′ for contacting different models of memory cards and reading data from the memory card. The metal contact lead terminal 27′ of the top cover 21′ must be connected to the first PCB 22′ such that the metal contact lead terminal 27′ of the top cover 21′ is coupled to the first PCB 22′. Further, a SMC card lead terminal 26′ of the top cover 21′ and a lead terminal (not shown in the figure) on the first PCB 22′ must be connected to an external second PCB 2″′ by a plurality of lead terminals (usually are the 50-pin lead terminals 29′) protruded from the rear end of the adapter 2′ so as to connect to the signals of the memory card read by the lead terminals of the top cover 21′ and the first PCB 22′, and the lead terminals of the SM card, MS card and SD card should be connected to an external second PCB 2 at the rear of the adapter 2′ of a chip device 2″ through a plurality of lead terminals protruded from the rear end of the adapter 2′ on the second PCB2. The length or the volume of a card reader is the sum of the lengths or volumes of the adapter and the external chip device and circuit. However, the mechanical design of the foregoing lead terminal not only increases the size of the card reader and adds a circuit board (which is a printed circuit board), but also elongates the signal line between the chip device and the lead terminals. As a result, the quality of the signal transmitted from the lead terminal of the circuit board will be lowered, and it is a pity for not properly maximizing the utility of the space within the adapter. The prior art is not only very complicated and requires adding a plurality of lead terminals (generally 50-pin terminals), but also increases the manufacturing cost.
The foregoing plurality of lead terminals is soldered onto the circuit board (PCB) for transmitting signals. Since there are many lead terminals used for the transmission, therefore the signal transmission becomes unstable and the failure rate rises. In other words, if one of the lead terminals is not soldered securely or the transmission is poor, then it will create a quality problem of the transmission to the adapter of the card reader, and such arrangement is definitely not an ideal design for signal transmissions. Further, the memory card slot in the adapter of a prior-art card reader is connected to a plurality of lead terminals (generally 50-pin terminals) by signal lines, such that the memory card slot can be electrically coupled to a circuit board (PCB) of the base. However, the installation of too many lead terminals relatively increases the manufacturing cost of the card reader, which is not cost-effective for product manufacturing. Therefore, the signal transmission of a prior-art card reader also requires further improvements.